The disclosed aspects relate generally to communications between and/or within devices and specifically to methods and systems for improving technology detection and collision resolution among multiple near field communication (NFC) devices using a NFC type-A radio frequency (RF) technology.
Advances in technology have resulted in smaller and more powerful personal computing devices. For example, there currently exist a variety of portable personal computing devices, including wireless computing devices, such as portable wireless telephones, personal digital assistants (PDAs) and paging devices that are each small, lightweight, and can be easily carried by users. More specifically, the portable wireless telephones, for example, further include cellular telephones that communicate voice and data packets over wireless networks. Many such cellular telephones are being manufactured with relatively large increases in computing capabilities, and as such, are becoming tantamount to small personal computers and hand-held PDAs. Further, such devices are being manufactured to enable communications using a variety of frequencies and applicable coverage areas, such as cellular communications, wireless local area network (WLAN) communications, NFC, etc.
The NFC Forum Activity specification defines a technology detection procedure to use when resolving multiple devices, tags, and cards that use NFC Type A (NFC-A) radio frequency (RF) technology. The process includes performance of a logical loop that is executed multiple times so as to differentiate each device in an operating volume. Further, the process includes a device sensing response (SENS_RES) to a device sensing request poll command (SENS_REQ). For NFC-A RF technologies, the device sensing response may indicate to the polling device information it may use to perform collision resolution. However, where there are multiple remote NFC devices (e.g., readers/writers, tags, cards, peer devices, etc.) in the operating volume, the device sensing response itself may suffer from collisions. The NFC Forum Activity Specification, as currently written, has the polling device perform collision resolution based on the originally received device sensing response. When the original device sensing response continues to be used for every iteration through the collision resolution process, a single device detect request (e.g., SDD_REQ) and/or a device sensing request generated in response to analysis of the received device sensing response can only be the best interpretation, by the polling device, of what combination of devices caused the original device sensing response collisions. In such an aspect, the polling device may be unable to determine what has been sensed if there are collisions in certain bytes of the SENS_RES. As such, the device sensing response used to remove ambiguity during the technology detection procedure is currently the response that may be the most ambiguous.
Thus, improved apparatus and methods for improving technology detection among multiple NFC-A devices may be desired.